Optimizing cerebrovascular endothelial health through shear stress modulation.

Area of Science:

• Cardiovascular research
• Neurovascular function
• Endothelial biology

Background:

• Endothelial dysfunction is a key risk factor for cerebrovascular diseases.
• Endothelial nitric oxide production is modulated by shear stress, impacting vascular adaptation.
• Internal carotid artery flow-mediated dilation (ICA-FMD) is a valuable in vivo method for assessing human cerebrovascular endothelial function.

Purpose of the Study:

• To review methodological advancements in ICA-FMD assessment.
• To consolidate mechanistic insights for improving ICA-FMD.
• To explore the impact of exercise on ICA-FMD and shear rate.

Main Methods:

• Synthesis of methodological advances in ICA-FMD assessment, including CO2 inhalation and shear stress normalization.
• Analysis of factors influencing ICA-FMD, such as intermittent hypoxia and exercise.
• Investigation of ICA shear rate during different exercise intensities and types.

Main Results:

• Standardized ICA-FMD assessment requires attention to CO2 levels, shear stress normalization, and ICA hemodynamics.
• Intermittent hypoxia enhances ICA dilatory response by increasing shear stress.
• Moderate-intensity leg cycling augments post-exercise ICA-FMD by increasing ICA shear rate, unlike high-intensity or small-muscle exercise.

Conclusions:

• A threshold shear stimulus is likely necessary for exercise-induced improvements in ICA-FMD.
• Standardized ICA-FMD methodologies and further research into shear stimulus thresholds are needed.
• Optimizing cerebrovascular endothelial function through enhanced ICA-FMD holds potential for preventing cerebrovascular diseases.